What is conservation biology?

Conservation biology is a mission-oriented science that focuses on how to protect and restore biodiversity, or the diversity of life on Earth. Like medical research, conservation biology deals with issues where quick action is critical and the consequences of failure are great. To preserve biodiversity, scientists must answer three general questions. First, how is the diversity of life distributed around the planet? Second, what threats does this diversity face? Third, what can people do to reduce or eliminate these threats and, when possible, restore biological diversity and ecosystem health?

What is biodiversity?

Biodiversity has three components:

All forms of life: biodiversity includes all living things -- including bacteria, fungi, plants, insects and other invertebrates, and vertebrates -- regardless of how similar they are to other species or how useful they are to people.

All levels of organization of living things: biodiversity includes individual organisms and their genetic material; groups of similar organisms, such as populations and species; and groups of species in communities, ecosystems and landscapes (groups of adjacent ecosystems).

All the interactions among the forms of life and their levels of organization: biodiversity is more than just the parts of a living system, such as genes, individuals and species -- biodiversity also includes the ways the various parts interact with each other, including competition, predation and symbiosis.

Why do scientists say there is a biodiversity crisis?

Scientists say there is a biodiversity crisis because the current rate of extinction is roughly 100-1,000 times faster than the natural rate. Besides diminishing the natural world around us, scientists believe that this loss of biodiversity will harm people. This is because we depend on nature for food, medicines (such as cancer treatments), industrial products (such as oils and resins), and vital ecosystem services (such as water purification, erosion control, and climate control).

The rate of extinction has accelerated throughout human history, and biodiversity loss is occurring throughout the world. More than 1,000 species are known to have gone extinct in the last 400 years, including the Passenger Pigeon and Stellar's Sea Cow. In addition, many subspecies have gone extinct. Subspecies are genetically distinct populations of a species and can be very different from each other. For example, the Greater Prairie Chicken and the Heath Hen are both subspecies of Tympanuchus cupido, and they are different sizes and live in different habitats. The Greater Prairie Chicken is larger and lives in the prairies of the Midwest, while the Heath Hen, which went extinct in 1932, was much smaller and inhabited coastal heath land from Massachusetts to Virginia.

Moreover, many other species and subspecies have declined so much that they are also in danger of going extinct. However, as dire as this sounds, there is some hope: because people are causing the current accelerated rate of extinction, we also have it within our power to slow it down or even stop it.

Why is biodiversity valuable?

Most conservation biologists recognize that biodiversity is valuable in two ways:
Biodiversity has utilitarian value because it benefits people directly and maintains interactions between the living and non-living parts of the environment. For example, biodiversity has provided plants for crops that feed billions of people, as well as decomposing organisms (such as bacteria and fungi) that release nutrients from organic material into soil and water.
Biodiversity also has inherent value to many people. In other words, it has worth beyond the goods and services it provides humans and ecosystems.

Why does biodiversity consist of several parts: genetic diversity, species diversity and ecosystem diversity?

The term "biodiversity" literally means "the diversity of life." This diversity occurs at three levels: genetic, species, and ecosystem. No one form of biodiversity is more important or more correct than any other. Rather, each represents a particular level of organization -- from the microscopic to the landscape -- that plays a unique role in how we can understand and appreciate all of the patterns and processes of life on Earth.

Genetic diversity: Individuals of the same species can have a variety of genetic traits, which can make the individuals different from each other. For example, some individuals may look different from each other while others may be more resistant to disease. Genetic diversity can allow individuals and populations to adapt to local environmental conditions. In addition, the loss of genetic diversity makes a species more prone to extinction.

Species diversity: Different regions of the Earth have different types and numbers of species (see "What is a species?"). For example, while the Arctic tundra contains fewer species than a tropical rainforest, these species are still important because they are adapted to the environmental conditions that are unique to this ecosystem. All of the different types of species distributed around the globe contribute to the patterns of life on Earth.

Ecosystem diversity: Different regions of the Earth also have different types and numbers of ecosystems (see "What is an ecosystem?"). The diversity of ecosystems is important because different ecosystems have different properties; for example, wetlands purify water and forests take up carbon dioxide from the atmosphere. In addition, ecosystems have patterns and properties that cannot be completely understood just by looking at the individual species. For example, by taking up carbon dioxide, forest ecosystems could help control global warming.

What is a species?

Life is so diverse that there is not a single definition of "species" that fits every organism. For organisms that reproduce sexually, a species is usually defined as a group of individuals that have the potential to produce fertile offspring. A classic example of this is the horse and the donkey, which are considered to be different species because even though they can breed with each other, they produce sterile offspring (mules).

However, there are some limitations to this way of defining species. For example, it can often be difficult to tell for sure whether a group of organisms has the potential to breed with each other, perhaps because some of them may be geographically isolated from each other. Moreover, the "fertile offspring" definition obviously does not apply to organisms that reproduce asexually, such as bacteria and some plants. Therefore, a species can also be defined as a collection of individuals that share particular physical or genetic traits.

Finally, biologists sometimes revise the way organisms are grouped into species. This is because new groupings can make more sense as we discover whether organisms actually produce fertile offspring, and learn more about the similarities/differences among organisms' traits.

What does endangered mean?

Under the 1973 Endangered Species Act (for more information on the Endangered Species Act go to http://www.epa.gov/region5/defs/html/esa.htm), a species is listed as endangered if it is "in danger of extinction throughout all or a significant portion of its range." Such species are more imperiled than threatened species, or those that are "likely to become endangered species within the foreseeable future." The status of a species (unlisted, threatened, or endangered) can change as we learn more about it or as we implement its recovery plan.

Why is protecting any one species important?

There are three answers to this question. First, if you believe that biodiversity has inherent value, then each species is valuable and should be protected from extinction. Second, the extinction of a single species may decrease the utilitarian value of nature. For example, if the species has economic value, its extinction clearly results in an economic loss.

Furthermore, if the species is important to other species or for the maintenance of important ecosystem characteristics, then its extinction can have undesirable cascading effects. For example, beavers dam streams and create networks of ponds that provide habitat for species like fish and ducks and that improve water quality and prevent erosion. The loss of beavers, therefore, would result in the loss of other species as well as of the ecosystem services provided by the habitat they create.

What is an ecosystem and how is it relevant to conservation biology?

An ecosystem comprises living and non-living components that interact with each other, such as plants and animals with nutrients, water, air and sunlight. Ecosystems range in size from a few square meters to millions of square kilometers. There are no set ecosystem boundaries, rather they are defined by the particular component(s) that biologists are interested in. For example, a biologist who wants to know how residential development has affected the fish in a stream ecosystem might study the small streams that feed into a large stream as well as the surrounding land. Such an ecosystem would cover many square kilometers and would include hundreds of living and non-living components.

While conservation traditionally focused on protecting single species, current practitioners often focus on protecting entire ecosystems or even groups of adjacent ecosystems, or landscapes. This trend increases the probability that we will protect the large-scale processes (such as nutrient cycling) that biodiversity depends on.

How do biologists measure biodiversity?

Because it is impractical or impossible to count every individual in most populations or communities (groups of populations), biologists measure biodiversity by first sampling the organisms and then extrapolating to estimate the total number of organisms. For example, to compare the number of bird species in different types of forest, biologists record the number and species of individual birds encountered at randomly selected locations within each forest type. Population biologists compare the average density of the individual species in each forest type. Community biologists compare the average number of species in a given area, such as a square meter or square kilometer, or the diversity index in a given area. The higher the diversity index, the more species and the more even the distribution of individual organisms among these species. Biologists interested in genetic or ecosystem diversity rely on similar sampling procedures and diversity indices.

What are biodiversity hotspots and where are they concentrated?

Biodiversity hotspots are areas that have large numbers of species and/or have many species that are not found anywhere else (endemic species). Conservation efforts in hotspots can protect or restore a relatively large part of the total biodiversity worldwide. Most biologists recognize about 25 global biodiversity hotspots that have many species as well as many endemic species. Most hotspots are in tropical regions, including the Amazon Basin, Central America, the Caribbean Islands, Western Africa, Madagascar, Western India and Southeast Asia. Many of these regions are hotspots because they have species-rich rainforests and coral reefs. However, there are also non-tropical biodiversity hotspots, including Central Chile, the Mediterranean Basin, South Africa, Eastern Europe, Central China, Western Australia, New Zealand and the Pacific Coast of the United States. Other hotspots in the U.S. include the southeastern region, California, and Hawaii.

What are the main threats to biodiversity?

The main threats to biodiversity are habitat loss and fragmentation, habitat degradation, introduced species, and over harvesting.

Habitat loss and fragmentation result from many processes including development, clearing land for agriculture, water diversion and logging. As more habitat is lost, the remaining fragments shrink and become more isolated from each other. This can keep animals from moving among fragments, which can increase inbreeding which results in decreased genetic diversity.

Habitat degradation involves disturbing key habitat features, such as extensive erosion or adding toxins to the soil or water. The most common causes of degradation are pollution and human recreation, such as off-road vehicles. Because habitat degradation is more subtle than habitat loss, its effects are often overlooked.

Introduced species are those that people have intentionally or inadvertently moved beyond their native range. Introduced species can wreak havoc on native species and ecosystems. For example, an introduced predator can eradicate native species that lack the ability to recognize or avoid it – after being introduced to several Caribbean islands, the mongoose led to the extinction of many reptiles and ground-nesting birds. In addition, introduced species can threaten native species by competing for limited resources such as space and water -- in the eastern United States, zebra mussels have endangered or led to the extinction of many native freshwater mussels by growing on top of them and so preventing them from feeding as well as by filtering so many food particles out of the water that the natives starve.

Over harvesting means hunting, fishing or collecting so many individuals from a species that it can no longer reproduce enough to withstand the harvest. Over harvesting has caused the extinction of many species worldwide, including the Passenger Pigeon in North America, the Great Auk throughout the North Atlantic, the Tasmanian wolf in Australia, the Moa in New Zealand, and the Dodo of the Indian Ocean island of Mauritius.

What are the best ways to conserve biodiversity?

The best way to conserve biodiversity is to protect it before it becomes endangered. To conserve biodiversity, we must:

Stop over harvesting species, such as elephants, rhinos, and tigers, leopards and other big cats;

Stop destroying habitats;

Stop polluting and otherwise disturbing habitats; and

Stop spreading non-native species.

We can also conserve biodiversity by reversing damage that has already been done. For example, we can restore natural communities by reintroducing native species and controlling invasive non-native species.

What are the best ways to conserve biodiversity?

Your library and local bookstore are good places to start. They have many books and magazines on these topics, ranging from descriptions of particular species and ecosystems to general discussions of biodiversity and conservation around the world. In addition, nature centers, natural history museums, zoological and botanical gardens, and aquariums also have a variety of activities and programs to help you learn more about the diversity of life on Earth. Many of these programs focus on the biodiversity of the local region or globe, and what you can do to help protect and restore it. Many organizations also have educational web sites with information about biodiversity (see "Conservation biology links"). Perhaps the best way to learn about biodiversity is to learn through direct experience. Visiting parks and natural areas either where you live or while you travel will help you gain a deeper understanding of biodiversity, and an appreciation for how you are connected to the full scope of life on Earth.

What can I do to help conserve biodiversity?

It's generally easiest to help conserve biodiversity in your local area or region. Before you actually do anything, you need to learn both about the local threats to biodiversity and about the most effective ways that you can counteract those threats. Begin by contacting or reading material from regional government natural resource agencies, non-governmental conservation organizations with regional offices (such as The Nature Conservancy), and regional universities or colleges with conservation biologists on the faculty.

There are five easy ways that you can help conserve biodiversity:

Personal behavior: Examples include turning your yard into a natural habitat by removing non-native species and landscaping with native plants; reducing waste production by buying products with less and/or recyclable packaging, recycling household goods, and composting vegetable waste for garden or flowerbed fertilizer; and limiting natural resource consumption and pollution by using public or non-motorized transportation, using fuel efficient vehicles, making your residence energy efficient, and disposing of chemicals properly rather than dumping them in sewers

Political activism: educate politicians on biodiversity issues and support politicians with good conservation records

Neighbor education: teach your neighbors about biodiversity, telling them why and how we should conserve it

Field assistance: for example, you can help monitor populations to identify those that are at risk of declining, and you can help restore native vegetation on public land

Where can I learn about how to become a conservation biologist?

Professional conservation biologists have at least a bachelor's degree in a conservation-related field, and most also have a master’s degree or a PhD. Talking to a conservation educator is the best way to learn about which educational path to take.

If you live near a college or a university, check relevant departments (such as biology, zoology, botany, natural resource management, wildlife science, and environmental science/studies) to see if any of the faculty members describe themselves as conservation biologists.

If you don’t have a local college or university, contact the Society for Conservation Biology (http://www.conbio.org/Services/Contact/) to find a member you can contact. Any of these professionals would be happy to give you advice on courses of study that would lead you into a conservation profession.